From: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Date: Tue, 8 Sep 2015 21:59:45 +0000 (-0700)
Subject: mm, dax: use i_mmap_unlock_write() in do_cow_fault()
X-Git-Tag: v4.1.12-92~18^2^2~94
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=b656f6fde87c2de7bfc97f3d07efde5df47d217e;p=users%2Fjedix%2Flinux-maple.git

mm, dax: use i_mmap_unlock_write() in do_cow_fault()

Orabug: 22913653

__dax_fault() takes i_mmap_lock for write. Let's pair it with write
unlock on do_cow_fault() side.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
(cherry picked from commit 52a2b53ffde6d6018dfc454fbde34383351fb896)
Signed-off-by: Dan Duval <dan.duval@oracle.com>
---

diff --git a/mm/memory.c b/mm/memory.c
index af2df84275bc..28d19905ebe4 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2995,9 +2995,9 @@ static int do_cow_fault(struct mm_struct *mm, struct vm_area_struct *vma,
 		} else {
 			/*
 			 * The fault handler has no page to lock, so it holds
-			 * i_mmap_lock for read to protect against truncate.
+			 * i_mmap_lock for write to protect against truncate.
 			 */
-			i_mmap_unlock_read(vma->vm_file->f_mapping);
+			i_mmap_unlock_write(vma->vm_file->f_mapping);
 		}
 		goto uncharge_out;
 	}
@@ -3011,9 +3011,9 @@ static int do_cow_fault(struct mm_struct *mm, struct vm_area_struct *vma,
 	} else {
 		/*
 		 * The fault handler has no page to lock, so it holds
-		 * i_mmap_lock for read to protect against truncate.
+		 * i_mmap_lock for write to protect against truncate.
 		 */
-		i_mmap_unlock_read(vma->vm_file->f_mapping);
+		i_mmap_unlock_write(vma->vm_file->f_mapping);
 	}
 	return ret;
 uncharge_out: